The present invention relates to the field of screen printing. Particularly, the present invention relates to an automatic method and apparatus for unloading or removing an article from a printing machine.
Printed indicia for applying to items of clothing, such as T-shirts, sweatshirts, golf shirts, shorts, hats, and the like, as well as other cloth and paper goods, such as banners, posters, bags, flags, and the like, have become very popular over the last 20 years. Boutiques specializing in printing fanciful and textual indicia such as slogans, college names, sports team names and logos, licensed characters, and the like, on these various media, are commonly seen in stores across the country. The indicia available at these stores can be pre-printed on a substrate and applied with a heated press by operators at such boutiques to any of the aforementioned items purchased by a consumer, or they can be screen printed directly onto the items for later purchase.
In the screen printing process, a stencil screen is typically blocked (called xe2x80x9cmaskedxe2x80x9d in the industry) to embody the desired indicia and is then placed over the item to be printed. Ink of one color is then added to the screen surface and flooded onto the indicia by a flood bar of conventional design. The ink may be of any type well-known in the industry for screen printing. After the ink is flooded onto the screen, the ink is squeegeed through the screen interstices onto the item, leaving ink of the desired color where the interstices in the screen are unblocked. The squeegee can be of any type known in the art.
After the item is printed on, it is moved to a station where one or more operators transfer the article to a drying rack, conveyor surface leading to a dryer, or the like. This requires quick and deft handling by the operator because the cycling of the printing machine may print a shirt every four to six seconds. Further, as the articles are typically adhered to the platen with an adhesive, the article must be lifted at an angle to break the adhesive seal without smudging the print on the article.
The quick, repetitive movement may take its toll on the operator after some amount of time. Therefore, it is advantageous to automate such a repeatable process. A few reasons for automatically unloading an article from a printing surface of a printing machine are: (1) to allow printing machine operators to concentrate on other areas of printing; (2) to diminish the likelihood of ruining printed articles; (3) to increase the repeatability of the exact placement of unloaded articles; and, (4) to reduce injury risk to printing machine operators.
In automating any task, it is often necessary to make alterations to existing equipment to accommodate new techniques or processes, especially where human senses, such as sight and touch, are being replaced by inanimate machinery. The present invention is no exception.
In accordance with the present invention, new methods and apparatus for unloading or removing an article from a printing machine, and preferably transferring the same to a suitable drying surface are provided. One embodiment of the disclosed apparatus includes a support frame, an extendable gripping means attached to the support frame for engaging the printed article, and a controller for controlling operation of the extendable gripping means.
Additionally, it is an aspect of the present invention to provide at least one platen attached to the printing machine in a manner allowing the extendable gripping means to vertically extend from the support frame to an area of the platen(s). To permit gripping of the articles, the platen are notched at the area corresponding to the extendable gripping means.
Alternatively, the platen may include a ledge at the area corresponding to the extendable gripping means. This ledge also allows the supported article to be gripped by the gripping means. The extendable gripping means may take a variety of forms including as a pair or numerous pairs of automatic jaws. Each automatic jaw corresponds to a ledge or notch of the platen.
It is an aspect of the present invention to prevent, or at least minimize, the ruining of the printed indicia by maintaining the article in a taut manner as it is unloaded from the printing machine. Accordingly, the present invention includes a telescoping rod for each vertically extending pair of automatic jaws. Preferably, the jaws, via the telescoping rods, will move diagonally upward from two ends of the article to slightly stretch the article upon lifting.
It is a further aspect of the present invention to provide a method of automatically unloading a printed article from a screen printing machine. Accordingly, in the disclosed method the article is positioned for printing on a platen having opposing first and second ends and at least one notch or a ledge on each of the two opposing ends. After the article is printed upon, it is automatically engaged with a gripping means at an area corresponding to each notch or ledge on the platen. The article is lifted from the platen with the gripping means at each engaged area simultaneously. This lifting from both ends of the article maintains tautness in the printed portion of the article as it is lifted from the platen.
These and other aspects of the present invention set forth in the appended claims may be realized in accordance with the following disclosure with particular reference to the accompanying drawings.